Abstract
Incubation of drug-resistant human tumor cells with a combination of prochlorperazine and dipyridamole has additive/synergistic effect on the cellular retention and cytotoxicity of doxorubicin. In patients administered a fixed dose of doxorubicin and prochlorperazine with escalating doses of dipyridamole, mean plasma levels of dipyridamole and prochlorperazine achieved were as high as 3.01 ± 0.41 μm and 0.94 ± 0.09 μm, respectively. Plasma samples from patients were analyzed in an in vitro assay to monitor the effect on the cellular retention of tritium-labeled daunorubicin in MDR1-transfected P388 cells. In 22 of 49 of the plasma samples analyzed, the daunorubicin in efflux blocking activity was one-half or greater than that of cells incubated with 12.5 μM verapamil, a well-known efflux blocker. These observations suggest that a combination of prochlorperazine and dipyridamole may enhance cellular doxorubicin retention by blocking efflux while reducing normal tissue toxicity and unwanted side effects in vivo.
Original language | English |
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Pages (from-to) | 1508-1517 |
Number of pages | 10 |
Journal | Clinical Cancer Research |
Volume | 6 |
Issue number | 4 |
State | Published - Apr 2000 |